1. Field of the Invention
This invention relates to water pumps and more particularly to a buoyant body containing a submersible electric pump for skimming water off a drilling mud reserve pit or the like.
Water based drilling mud is commonly used in rotary drilling of oil and gas wells. The water content of such mud is usually 90% or more.
One purpose of the drilling mud is to remove formation cuttings from the well bore.
During the drilling process excess mud accumulates and waste mud is deposited in a reserve pit where the solids precipitate out of the fluid and water collects on the top thereof. In addition to the water, normally in the waste mud, wash water from washing the rig and rain also collects with the mud in the reservoir. On an oil or gas well drilled to a depth of 10,000 feet, the waste mud and water necessary to be disposed of may average 8-12,000 barrels. The usual method of disposal is trucking the mud to an open pit at a disposal site and allowing the mud to settle and the water to dehydrate or by pumping the mud down hole between the production casing and a well bore into a nonproductive formation.
Both disposal methods create an obvious environmental pollution problem.
This invention, in part at least, minimizes the waste mud disposal problem by reusing water collecting on drilling mud when in a reserve pit. Thus, also reducing the quantity of additional fresh water ordinarily purchased for use with the drilling mud in maintaining its viscosity at a desired ratio.
2. Description of the Prior Art
The most pertinent patent is believed to be U.S. Pat. No. 4,789,307 which discloses a box-like housing having its upper portion filled with buoyant foam for supporting the housing. The housing contains a battery powered sump pump in its depending portion. The housing bottom wall is provided with openings for admitting water for pump removal.
This invention is believed to be distinctive over this patent by providing a substantially disc-like buoyant body having a central depending sump pit for supporting a sump pump and removing water entering the pit through its apertured wall.